1 Features
1• IEEE 802.3at Quad Port PSE controller
– Auto Detect, classification
– Auto Turn-On and disconnect
– Efficient 255-mΩ sense resistor
• Pin-Out enables Two-Layer PCB
• Kelvin Current Sensing
• 4-Point detection
• Automatic mode – as shipped
– No External terminal setting required
– No Initial I2C communication required
• Semi-Automatic mode – set by I2C command
– Continuous Identification and Classification
– Meets IEEE 400-ms TPON specification
– Fast-Port shutdown input
– Operates best when used in conjunction with
system reference code
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• Optional I2C control and monitoring
• –40°C to 125°C Temperature range
• TSSOP 28 Package 9.8 mm x 6.6 mm

2 Applications
• Ethernet switches and routers
• Surveillance NVR and DVRs
• Residential gateways
• PoE Pass-Through systems
• Wireless backhaul

3 Description
The TPS23861 is an easy-to-use, flexible,
IEEE802.3at PSE solution. As shipped, it
automatically manages four 802.3at ports without the
need for any external control.
The TPS23861 automatically detects Powered
Devices (PDs) that have a valid signature, determines
power requirements according to classification and
applies power. Two-event classification is supported
for type-2 PDs. The TPS23861 supports DC
disconnection and the external FET architecture
allows designers to balance size, efficiency and
solution cost requirements.
The unique pin-out enables 2-layer PCB designs via
logical grouping and clear upper and lower
differentiation of I2C and power pins. This delivers
best-in-class thermal performance, Kelvin accuracy
and low-build cost.
In addition to automatic operation, the TPS23861
supports Semi-Auto Mode via I2C control for precision
monitoring and intelligent power management.
Compliance with the 400-ms TPON specification is
ensured whether in semi-automatic or automatic
mode.